Abstract
Among the different types of photonic sensor devices, optical whispering gallery mode resonators (WGMRs) have attracted interest due to their high level of sensitivity, small size, and ability to perform real-time temperature measurements. Here we demonstrate the applicability of temperature measurements using WGMR in both air and liquid environments. We also show that WGMR allowed measurements of the refractive index variations in an evaporating glucose–water solution droplet. The thermal tuning of WGMR can be reduced by coating WGMRs with a thin layer of polymethyl methacrylate (PMMA). Dip-coating the silica microsphere multiple times significantly reduced the resonance shift, partially compensating for the positive thermo-optical coefficient of silica. The shift direction changed the sign eventually.
Highlights
Using the Rb saturation spectroscopy signal as a reference, it was possible to eliminate laser drift from the temperature-induced Whispering gallery mode resonators (WGMRs) resonance shift
The results suggest the presence of an additional resonance shift mechanism in the glucose solution drop
We have demonstrated the applicability of temperature measurements using the WGMR in both air and liquid environments
Summary
Whispering gallery mode resonators (WGMRs) have attracted significant interest because of their extreme sensitivity, compactness, fast responses, and real-time measurements.WGMRs have been used in various applications, such as temperature sensors [1,2,3,4], pressure and force sensors [3], humidity sensors [5,6], accelerometers [7], and biosensors [8,9,10].WGMRs show ultra-high quality (Q) factors and ultra-narrow linewidth resonances that allow achieving very high resolution and detecting extremely small incremental changes of parameters [11].WGMR sensors’ operational principles are based on a shift of the resonance frequencies or resonance width due to external influences. Whispering gallery mode resonators (WGMRs) have attracted significant interest because of their extreme sensitivity, compactness, fast responses, and real-time measurements. WGMRs have been used in various applications, such as temperature sensors [1,2,3,4], pressure and force sensors [3], humidity sensors [5,6], accelerometers [7], and biosensors [8,9,10]. WGMRs show ultra-high quality (Q) factors and ultra-narrow linewidth resonances that allow achieving very high resolution and detecting extremely small incremental changes of parameters [11]. A common method for recording the WGMR resonance spectrum is the laser frequency scan method. A slow frequency scan of the laser is finely done by sweeping through the resonances, and the transmission signal is recorded
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
